On Tue, Feb 27, 2007 at 06:26:18AM -0800, Geoffrey Broadwell wrote: : What happens when you cast between low-level types? If the source value : is out of range of the destination type, do you get: : : 1. An exception? : 2. Clip to finite range always? : 3. Clip to finite range for ints, clip to infinities for nums? : 4. Exception when dest is int, clip to infinities when dest is num? : 5. Copy bits that fit from source to dest and reinterpret? : : Personally, I think option 1 or option 4 make the most sense for : conversion between int, uint, num, and complex types, while either : option 1 or option 5 make sense for conversion to/from buf types.
Basically it's 4, except that the exception is a warning (which is a form of resumable exception in Perl 6.) : Also, when casting from a num type to an int type, is there a way to : specify desired rounding/truncation behavior in a way that allows the : most efficient code under the covers, rather than making a side trip : through Num and Int? Depends on what you call to perform the rounding. Could be anything from a macro to a multimethod. The default round() is presumably a multimethod on Num that produces an Int, but you can always define more specific multis or functions or macros, or whack the compiler upside the head with a pragma. Larry
